A significant problem in the study of human oral communication concerns how we utilize various types of sensory feedback in controlling the complexly patterned muscle contraction required for speech productions. The purpose of this research is to further our understanding of how auditory and perioral receptors function in the motor control of lip movements during speech. Auditory receptor function is to be studied by means of experiments in which normal auditory feedback is systematically disrupted while measures of lip movement and muscle activity are simultaneously recorded. Perioral receptor function will be studied by applying precisely defined mechanical stimuli to the lips during passive and active muscle conditions while potentials from selected facial muscles are recorded. Analysis of these two sets of data should provide significant insight into the servo control properties of auditory and perioral receptors as they function in speech motor control. Such information will be essential for the development of speech production models which are to have significant utility in the diagnosis and treatment of various speech disorders.